1. Field of the Invention
The present invention relates to conveyor belts. More specifically, the present invention relates to an improved metal conveyor belt specifically used the manufacture of lids for can. The present invention provides a means wherein lids disposed on a conveyor belt are more firmly affixed to the belt surface. As a result, the lids are less likely to rotate during the various processes of manufacture.
Can lids are subjected to many stresses as they are conveyed from one manufacturing station to another. As a result, the lids have a tendency to rotate within the holes in the conveyor belt in which they are placed. The rotation of the can lids prevents quality manufacture of the features on the lid. As a result, the lids must be discarded or recycled.
In addition to the difficulties encountred as the can lids are conveyed from one location to another, the can lids are subject to numerous forces during a specific manufacturing process. As a result, it is necessary to fine a means that can hold the can lid in place during the specific manufacturing stage.
Persons have tried to remedy this situation by incorporating rubber conveyor belts into the manufacturing process. However, these rubber belts have a tendency to disintegrate during their lifespan. As a result, the belt leaves small particles of rubber on the can lids. This is an unsanitary condition requiring additional expense to clean the lids before attachment to the cans themselves. Moreover, the rubber belts cost approximately four times that of a metal belt. Thus, the metal belt is preferred from an economic standpoint.
2. Description of the Prior Art
Other inventors have patented conveyor belt systems in this field. U.S. Pat. No. 3,231,065 issued to E. G. Kaminski et. al. on Jan. 25, 1966 discloses an apparatus which is particularly exemplary of the type of conveyor system upon which the present invention improves. Kaminski et. al. teaches that can lids can be stamped if they are conveyed on a conveyor belt that has holes in it to hold the lids in place. However, the problem associated with this particular system is that the can lids rotate in an unacceptable fashion. This creates the need to restamp can lids. As may be obvious, when the percentage of improperly stamped lids becomes large, so too does the cost associated with remanufacture.
The problem of the rotation of can lids on a conveyor belt is a twenty-five year old problem. Many have attempted to correct this difficulty. Primarily, the most common form of correction has revolved around the use of rubber conveyor belts and the like. However, the use of rubber conveyor belts brings to light an additional problem. Foremost of the problem is the unsanitary degradation of these belts during use wherein small particles of rubber become deposited on the can lids.
In reference to the lifespan of rubber belts, it compares well to that of metal belts. In fact, the lifespan of a rubber belt slightly exceeds that of a metal belt. However, as the rubber belt is used, small particles of rubber become dislodged from the surface and contaminate the can lids. This is a wholly unacceptable condition where the can lids must be kept clean to avoid human consumption. Moreover, keeping can lids free of these contaminants require complex and expensive servicing. Couple this with the fact that rubber conveyor belts cost about four time that of a metal belt, the metal belt becomes a wise economic choice.
The current process utilizes a vacuum device to hold the can lids in place during a specific stage of manufacture. Due to the usual low frictional force between the can lids and the metal surface, the vacuum that heretofore has been applied was relatively high. Moreover, the application of strong suction through a vacuum is very costly. The present invention, because it introduces additional forces between the lid and the conveyor belt, reduces the need for a strong vacuum. Therefore, the overall cost of manufacture is concordantly reduced.
The present invention is a modification of metal conveyor belts which greatly increases the utility of metal conveyor belts in the area of tin can manufacture. Tin can is a generic term for cans which may be constructed of any suitable material such as aluminum. The present invention incorporates a rough groove around the hole in the conveyor belt in which the edge of the can lid sits when placed on the conveyor belt. The rough surface is of a sufficient roughness to prevent the can lid from rotating as it is conveyed from one manufacturing station to another.
The problem of lid rotation has been known since the issuance of the Kaminski patent. However, it has not been until now that a viable solution could be employed to improve the reliability of die casting and stamping. The present invention solves this twenty-five year old problem. It substantially reduces the probability that the can lids may rotate.